Several concepts and architectures are known in the art for providing communication services over communication networks. For example, the Intelligent Network (IN) is an architectural concept that enables real-time execution of network services and customer applications in a distributed environment of interconnected computers and switching systems, such as wire-line and wireless telephone networks. IN standards have been promulgated by the International Telecommunications Union (ITU-T) and by the American National Standards Institute (ANSI). The IN concept is described, for example, by Faynberg et al., in “The Development of the Wireless Intelligent Network (WIN) and Its Relation to the International Intelligent Network Standards,” Bell Labs Technical Journal, Summer, 1997, pages 57-80, which is incorporated herein by reference.
Another example of a standardized service provisioning architecture is the Internet Protocol Multimedia Subsystem (IMS) architecture. The IMS architecture is defined and described in a 3rd Generation Partnership Project (3GPP) standard entitled “Technical Specification Group Services and System Aspects; IP Multimedia Subsystem (IMS); Stage 2 (Release 7),” 3GPP TS 23.228, version 7.2.0, December 2005, which is incorporated herein by reference. The IP multimedia core network (IM CN) subsystem enables Public Land-Mobile Network (PLMN) operators to offer their subscribers multimedia services based on and built upon Internet applications, services and protocols. The IMS architecture is described, for example, in a whitepaper published by Lucent Technologies Inc. (Murray Hill, N.J.), entitled “IP Multimedia Subsystem (IMS) Service Architecture,” February, 2005, which is incorporated herein by reference.
Signaling in IMS networks is typically performed in accordance with the Session Initiation Protocol (SIP). SIP is described by Rosenberg et al., in Request For Comments (RFC) 3261, published by the Internet Engineering Task Force (IETF), entitled “SIP: Session Initiation Protocol,” June 2002, which is incorporated herein by reference.
Various techniques for providing services across multiple communication domains are known in the art. For example, PCT International Publication WO 2006/077587, whose disclosure is incorporated herein by reference, describes a method for communication in a communication system that includes a circuit-switched network and a packet-switched network. The method includes accepting a request to set up a call for a communication terminal associated with one of the circuit-switched network and the packet-switched network. The call is established with the one of the circuit-switched network and the packet-switched network responsively to the request. During the call, a first service platform in the circuit-switched network is invoked to provide a first call service, and a second service platform in the packet-switched network is invoked to provide a second call service to the communication terminal.
As another example, U.S. Patent Application Publication 2007/0263599, whose disclosure is incorporated herein by reference, describes a method for communication. The method includes predefining a plurality of service delivery modes having different signaling and media path configurations in circuit-switched and packet-switched networks. A request to place a call is accepted in the circuit-switched network, and a call service to be provided to the call by a service platform in the packet-switched network is identified responsively to the request. A service delivery mode is selected from the plurality responsively to an attribute of the call indicated by the request. Signaling and media paths are established for the call via the circuit-switched and packet-switched networks in accordance with the signaling and media path configurations of the selected service delivery mode. The call service is provided from the service platform to the call using the established signaling and media paths.